Step 1 – Add Oils to Slow Cooker
Pour all oils — except for the peppermint essential oil — into the slow cooker. Then, turn on the slow cooker, and place it on the highest setting.
Step 2 – Mix Water and Lye
Warning: Working with lye can be dangerous because it is caustic and can burn the skin. Wear safety gloves and goggles, and keep children and pets out of the work area. In addition, complete this step outside for proper ventilation.
Outside, pour 8 ounces of water into your bowl. Do not pour the water into the lye because it could cause a violent reaction and overflow. Instead, slowly add the lye to the water, and stir until the lye is dissolved.
Step 3 – Add Lye Solution to Oils
Next, pour the lye solution into the oils in the slow cooker. Use a stick blender to blend the mixture. Continue blending until the mixture thickens to the consistency of runny pudding, or is “trace.” Once the mixture has reached trace, you can stop blending.
Letting It Cool
Allow the mixture to cook until it becomes thick but not stiff. Use the spoon to take a sample of the soap. Place the sample on a plate. If it solidifies as it cools, the soap is ready. If it is still runny, allow it to cook for longer.
Step 4 – Add Essential Oil
When the soap is finished, turn off the slow cooker. Stir the soap to encourage cooling, and use a candy thermometer to check the temperature. Once the temperature is below 153 degrees, the point at which the peppermint essential oil will not burn off, add 20 drops of the peppermint essential oil to the soap. Stir vigorously.
Alternatively, use different essential oils in your soap for different scents, like patchouli or jasmine.
Step 5 – Mold the Soap
Lubricate the soap molds or muffin tins lightly with olive oil. Pour a few drops of oil into each mold, and use your fingers to coat the entire surface. Then, pour the soap mixture into the molds. Try to do this quickly because the soap will solidify once it has cooled.
Releasing Air Bubbles
Once you have filled the molds, shake them back and forth to release any air bubbles trapped in the soap. Allow the soap to sit for at least 24 hours before using it in the following steps. If you would prefer to use a bar of all-natural shampoo soap instead of a liquid, you can stop here.
Step 6 – Grate Soap
Grate 4 ounces of soap using a grater. Grate it as finely as possible. After doing this, you can also make decorative soap balls with your grated soap.
Step 7 – Dissolve Soap and Add Glycerin
Next, boil 12 ounces of water in a saucepan. Add the grated soap, and stir until the soap has completely dissolved into the water. Then, add the glycerin to the dissolved soap solution. Stir it thoroughly.
Step 8 – Add Essential Oil
Mix 10 drops of peppermint essential oil into the soap solution to give the shampoo an invigorating scent and prevent bacterial growth. If you store the homemade shampoo in the refrigerator between uses, it will stay good for two weeks.
What you’ll need:
- 4 oz. jojoba oil
- 4 oz. castor oil
- 8 oz. extra-virgin olive oil, plus extra for molds
- 20 oz. water
- 2.74 oz. lye
- 1 1/2 tablespoons vegetable glycerin
- Stick blender
- Slow cooker
- 30 drops peppermint essential oil
- Candy thermometer
- Safety glasses
- Glass or stainless-steel bowl
- Stainless-steel or wooden mixing spoon
- Soap molds or muffin pans